A conventional switch device, especially for those switches using a bimetallic plate to prevent from being burned when it is overloaded, generally includes a bi-metallic plate which is deformed when the switch device is overloaded so as to separate the two contact points respectively located on the bi-metallic plate and one of the two terminals of the switch device. Some inherent shortcomings for these conventional safety switch devices are found. There are too many parts involved in the safety switch device and a longer period of time is required when assembling the switch device, and this increases the cost of the products. The parts might be arranged inaccurately and affect the deformation of the bi-metallic plate. Once the bi-metallic plate is deformed to cut off the circuit, because of the improper arrangement of the parts as mentioned above, the bi-metallic plate could deform to re-connect the two contact points to connect the circuit again. Because of the inaccuracy of the deformation of the bi-metallic plate, the switch member does not set the “OFF” position properly after the bi-metallic plate is deformed to cut off the circuit.
Therefore, it is desired to have a safety switch wherein the bi-metallic plate is ensured to have proper flexibility and deformed to separate the two contact points when the safety switch is overloaded.